Sigma 18-50 mm F2.8 EX DC lens

Sigma has today announced a further extension to its range of DC lenses
which are designed specifically for digital SLR's. The new 18-50 mm F2.8
EX DC has a very usable 18 mm wide angle (approx 28 mm FOV on a digital
SLR) to 50 mm telephoto (approx. 2.7x zoom). Like all DC lenses the image
circle produced by this lens is designed to be just the right size for
APS size sensors and hence allows the lens to be more compact than it
would otherwise be.

Press Release:

Sigma 18-50mm F2.8 EX DC

EX series, large aperture zoom lens designed specifically for use with
digital SLR cameras

EX lens series denotes excellence of engineering and new technology.

Compact and lightweight zoom despite large F2.8 aperture.

Excellent correction for various types of aberration provided by one
SLD (Special Low Dispersion) glass element and two aspherical lenses.

F2.8 large aperture standard zoom lens designed specially for use with
digital SLR cameras.
The characteristics of digital SLR cameras were taken into consideration
when designing the lens power layout. The new advanced lens design corrects
various aberrations. This lens provides the utmost correction against
lateral chromatic aberration which is a serious problem for digital SLR
cameras.

This lens is specially coated to get the best color balance whilst cutting
down flare and ghost caused by reflections from the digital image sensor
and lens. It has excellent correction for vignetting and superior peripheral
brightness is ensured.

A Special Low Dispersion (SLD) lens and two aspherical lens elements
provide excellent correction for all types of aberrations. The design
produces a compact and lightweight, yet robust, construction with an overall
length of 84.1mm (3.3in.) and maximum diameter of 74.1mm (2.9in.) and
weight of 445g (15.6oz).

This lens has a minimum focusing distance of 28cm (11in.). It is equipped
with inner focusing system. The non-rotating front lens element makes
the lens suitable for using its petal-type lens hood and circular polarizing
filters.